The invention relates to the food industry sector. It relates more precisely to a novel method allowing the processing of plant products and in particular of fruits, vegetables, mushrooms and aromatic herbs, enabling preservation of these plant products without any chemical, natural or artificial additive. The fruits and vegetables obtained by this method, and the purees produced from these fruits, or the liquid extracts obtained during the method have multiple uses, in particular in relation to chocolate.
In the remainder of the description, the method is essentially described in its application to the processing of fruit, but it may be transposed for numerous other types of plant products.
As is known, fruits are frequently used in numerous food preparations, in particular in confectionery, in which they are often combined with chocolate.
More precisely, to manufacture fresh fruit coated with chocolate, it is essential to incorporate a fraction of crxc3xa8me fraîche or of another fatty substance into the chocolate, so that the mixture adheres to the fruit. It is quite obvious that the use of a fatty substance involves very demanding preservation conditions.
Moreover, to obtain good adhesion of the chocolate to the fruit, it is also possible to coat it with a layer of sugar and/or starch to which the chocolate adheres. Unfortunately, this method modifies the taste of the confectionery by making it more sweet, and requires an additional operation which will extend the manufacturing time.
At present, the only technique known for causing chocolate to adhere to a fruit consists in using fruits previously impregnated with alcohol, which substantially limits the range of products which can be produced. At present, xe2x80x9cdirectxe2x80x9d adhesion of chocolate to a fruit can only be achieved after having impregnated the fruit with alcohol. Only Morello cherries, raspberries and a few other fruits are currently processed in this way.
The first problem which the invention therefore proposes to solve is that of the possibility of combining fresh fruit or pieces of fruit with chocolate, without adding any additive or intermediate agent.
Moreover, if it is desired to incorporate a fraction of fruit purxc3xa9e to chocolate in order to produce a spread, it is necessary to add to the mixture a fraction of crxc3xa8me fraîche or of a fatty substance, which has the abovementioned disadvantages.
Furthermore, the quantity of fruit purxc3xa9e which can be incorporated will be limited by concerns about preservation over time. Indeed, in the absence of preservative, it is impossible to obtain fruit purxc3xa9e/chocolate mixtures containing more than 10% of fruit, without the risk of molds appearing.
The second problem which the invention therefore proposes to solve is the possibility of increasing this proportion of fruit purxc3xa9e which can be incorporated into chocolate.
In general, the incorporation of whole fruits or of fruit purxc3xa9e into milk foods is of great interest (manufacture of fruit yogurt for example). However, for preservation considerations, it is necessary that the fruits used on the production line for these products are treated beforehand. This may be carried out by chemical treatment or preservation methods, or even a combination of both.
By way of example, and as described in patent EP 327 543, fruits can be subjected to different stages of a process intended to ensure their good preservation. More precisely, as described in the abovementioned document, the fruits are mixed with granulated sugar so as to increase the sugar content of the fruits while heating.
Such a heating is particularly damaging since it tends to degrade and soften the fruit, and therefore to reduce its capacity to absorb sugar. Moreover, the vigorous mixing, mentioned above, which unavoidably causes the crushing of the fruits, reinforces their inability to absorb an additional quantity of sugar. This method therefore requires the addition of specific chemical products such as citrates or other acidifying agents, intended to enable the preservation of the products.
Another problem which the invention therefore seeks to solve is to enable a practically perfect preservation of the fruits, without adding any chemical, natural or artificial additive, in order to allow the incorporation of the fruits into numerous food preparations.
In the document U.S. Pat. No. 4,713,252, there is described a method for processing bilberries in order to produce a purxc3xa9e having enhanced taste qualities. According to this method, the bilberries are immersed in a vessel containing granulated sugar. The bilberries are kept inside this vessel for several hours, while undergoing heating. An osmotic phenomenon occurs between the bilberries and the sugar in which they are placed. The heating undergone by the fruits causes the abovementioned disadvantages, namely softening of the fruit, and therefore a reduction in its capacity to absorb sugar.
The invention therefore proposes to provide a novel method for processing fruits which allows optimum preservation thereof without the use of any chemical, natural or artificial product, the fruits thus obtained being easily incorporated into many food preparations, and in particular some which include chocolate.
The invention therefore relates to a method for processing plant products comprising an aqueous fraction, in particular for the production of foods based on such plant products.
This process is characterized in that it consists:
in placing plant products and granulated sugar in a chamber, the weight of sugar representing at least 20% of the weight of plant products;
in allowing the sugar to flow by gravity inside the chamber around the plant products, while maintaining the chamber at a temperature of less than or equal to room temperature;
recirculating the sugar which has flowed to the bottom of the chamber, so as to ensure that it is constantly circulated around the plant products and that the sugar is absorbed by the plant products, and that part of the aqueous fraction of the plant products is exuded.
In other words, the invention consists in bringing the plant products into contact with solid sugar, such that a large portion of the water contained in these plant products comes out therefrom, and is present in the solid sugar, and that, conversely, part of the granulated sugar penetrates into the plant product.
The expression sugar is understood to mean granulated sugar such as sucrose, but also fructose, dextrose, or any other type of solid sugar. The expression plant products is understood to mean fruits, vegetables, as well as mushrooms, and aromatic herbs, flowers, flowering tops and more generally the plant products used as food in a broad sense.
Thus, using the method in accordance with the invention, the amount of plant product product dry extract is very substantially increased. The contact is maintained until there is complete absorption of the sugar, that is to say up to the moment the plant material is saturated with sugar and no longer absorbs it.
Such a method therefore makes it possible to obtain a liquid fraction consisting of sugar dissolved in the juice of the plant product corresponding to the aqueous fraction extracted from the plant product, and in which the treated plant products are immersed.
It is therefore possible, depending on the desired applications, to extend the method by separating the liquid fraction and the treated plant product, or by grinding the treated plant product alone or with part of the liquid fraction.
Surprisingly, it has been observed that by carrying out the operation in accordance with the invention, the amount of fructose and glucose present inside the fruit (or more generally the plant products) is much higher than that measured in natural fruits, whereas the added sugar is sucrose. Thus, the method in accordance with the invention appears to result in a chemical conversion of the sugar used.
In a particularly surprising manner, it is observed that the fruits treated, when they are separated from the liquid fraction, exhibit an excellent preservation capacity, and that they can be preserved in an ambient atmosphere for several days, or even several weeks, without undergoing any degradation. This is found to be particularly advantageous for many applications, using mellow or dried fruits.
In practice, it was observed that the preservation was particularly enhanced when the weight of sugar represents between 80 and 120% of the weight of plant products.
Also surprisingly, it was observed that the treated fruits had a very good capacity to be mixed directly with chocolate, without requiring the addition of any foreign fatty substance, of which the disadvantages were specified above.
Advantageously, the fruits and vegetables used (and more particularly the plant products) may be whole fruits or vegetables as well as precut or presliced fruit or vegetables.
The fruits and vegetables may be fresh or may have been previously subjected to a freezing stage.
In practice, avoid possible problems relating to the fermentation of the fruits, it may prove advantageous to maintain said chamber at a temperature of less than 6xc2x0 C. For some fruits, and in particular for pears, it may prove advantageous to work at a lower temperature, of between xe2x88x925 and xe2x88x9210xc2x0 C.
Advantageously in practice, the chamber may also be maintained under a reduced pressure, so as to limit the quantity of oxygen capable of causing fermentation phenomena.
Several techniques may be used for maintaining the flow of the sugar around the fruit, and to ensure constant circulation as the sugar is absorbed.
Thus, in practice, in a first embodiment, it is possible to modify the inclination of the chamber relative to the vertical, so that the fraction of the sugar which has flowed to the bottom rises to the upper part of the chamber. In this manner, the rise of the slightly impregnated sugar is brought about, so as to allow it again to trickle over the fruits.
In a second embodiment, it is possible to ensure the rise of the sugar via a pumping system, which collects the sugar which has flowed to the bottom of the chamber, and which reinjects this fraction of soaked sugar at the top part of the chamber. In this embodiment, the chamber remains fixed and causes no movement of the fruits throughout the process.
In another embodiment, it is possible to mechanically mix the fruits inside the chamber by the action of a paddle or of an equivalent means. This solution leads to a result of less satisfactory quality for certain types of fruits, since the latter are then subjected to mechanical stress which can cause their degradation, and consequently poor absorption of the sugar.
The invention also relates to the treated fruits which can be obtained according to the method, as well as the fruit purxc3xa9e produced from these fruits. Such a purxc3xa9e can therefore be advantageously combined with chocolate for the production of unctuous spread or of chocolate filling, or of chocolate and fruit truffles.
The invention also relates to the liquid fruit extract obtained after the separation of the liquid fraction collected at the end of the process.
The manner of carrying out the invention as well as the advantages resulting therefrom will emerge clearly from the description of the embodiments which follow.
As already stated, the invention relates to a method for processing plant products, and more particularly fruits, which makes it possible to obtain fruits exhibiting excellent preservation capacity, without any addition of chemical products and preservatives, and the like, and which exhibit, in addition, good capacity to be incorporated into many food preparations, such as in particular those including chocolate.